id:A055235 - OEIS Search Results

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Sums of two powers of 3.

+0
4

2, 4, 6, 10, 12, 18, 28, 30, 36, 54, 82, 84, 90, 108, 162, 244, 246, 252, 270, 324, 486, 730, 732, 738, 756, 810, 972, 1458, 2188, 2190, 2196, 2214, 2268, 2430, 2916, 4374, 6562, 6564, 6570, 6588, 6642, 6804, 7290, 8748, 13122, 19684, 19686, 19692, 19710 (list; table; graph; listen)

	OFFSET	`0,1`
	FORMULA	`a(n) = 3^(n-trinv(n)(trinv(n)+1)/2)+3^trinv(n), where trinv(n) = floor((1+sqrt(1+8n))/2) = A002262(n) and n-trinv(n)*(trinv(n)+1)/2 = A003056(n)` `Regarded as a triangle, T(n, k)=3^n+3^k`
	EXAMPLE	`a(4) = 12 = 3^2+3^1`
	CROSSREFS	`Cf. A052216.` `Sequence in context: A045958 A076067 A065385 this_sequence A083887 A064374 A000885` `Adjacent sequences: A055232 A055233 A055234 this_sequence A055236 A055237 A055238`
	KEYWORD	`base,easy,nonn,tabl`
	AUTHOR	`Henry Bottomley (se16(AT)btinternet.com), Jun 22 2000`

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.

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